In signal processing it is often desirable and sometimes even necessary to provide an indication of signal power. For example, in high frequency RF wireless applications the RF carrier can be envelope modulated with a signal having a high crest factor; and under these and similar circumstances, it may be desirable to provide an indication of the average power provided by this signal. One technique is to apply the signal to a power measurement circuit which is designed to provide a signal representing the square of the input as an indication of its average power, which is an accurate measure regardless of the signal's crest factor. Such an approach is described in U.S. Published Application No. 2008/0136491 dated Jun. 12, 2008, based upon an application filed on Dec. 6, 2006 in the name of Min Z. Zou, and assigned to the present assignee, wherein a squaring cell (x2) is coupled to an averaging RC filter in order to provide an average power measurement of the input signal. Other circuit power measurement implementations are shown and described in U.S. Pat. No. 4,639,623 issued to Pullen on Jan. 27, 1987, and U.S. Pat. No. 6,172,549 issued to Gilbert on Jan. 9, 2001 (the “Gilbert Patent”).
In some RF applications, RF signals routed on a circuit board are single-ended, and must interface with the differential input of a power measurement circuit through an interface in the form of a balun transformer, which increases the cost and complexity of the circuit. It is desirable to provide a power measurement circuit which is provided with a single-ended input eliminating the need for a balun transformer.